IL6 and COVID-19: In line with previous reports [18], COVID-19 patients with severe condition were more likely to be older, present respiratory and gastrointestinal symptoms, and have higher circulating levels of inflammation biomarkers (e.g., CRP), immune cells (e.g., lymphocyte, CD4+, CD8+), and cytokines (e.g., IL-6, IL-10) (all P < 0.05, Table 1).